In Patent Literature 1, there is a description of a “navigation device including: travel route data storage means for storing travel route data indicating a planned travel route along which a vehicle driven by a user is to travel; correlation data storage means for storing workload correlation data indicating a correlation between a behavior by the user and a workload of the user during vehicle travel; planned presentation information storage means for storing planned presentation information, which is information planned on being presented to the user when traveling along the travel route; user behavior estimation processing means for performing user behavior estimation processing to estimate, based on the travel route data, a behavior of the user during travel along the travel route; workload prediction processing means for performing workload prediction processing to predict, based on the estimated behavior of the user and the workload correlation data, a workload corresponding to the behavior of the user during travel along the travel route; scheduling processing means for performing scheduling processing to determine, based on the predicted workload, a timing at which the planned presentation information is to be presented to the user when traveling along the travel route; and information output means for outputting the planned presentation information to the user at the determined timing”.